Lighting-fixture.



L. E. GRISWOLD.

LIGHTING FIXTURE. APPLICATION FILED nc.12.1a|4

Patented Ma; 1, 1917 2 SHEETS-SHEET 1.

Fly. 1

INVENTOR' ATTORNEYS L. E. GRISWOLD.

LIGHTING FIXTURE.

APPLICATION FILED DEC. 12. 1914.

1,2%,162.. Patented May 1, 1917.

2 SHEETS-SHEET 2- WITNESSES INVENTOR ATTORNEYS mar, are.

LESTER E. GRISWOLD, 0F PITTSBITRGH, PENNSYLVANIA, ASSIGNOR TO MACBETH- EVANS GLASS COMPANY, OF PITTSBURGH, -PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

LIGHTING-FIXTURE.

Specification of Letters Patent.

Patented May 1, 191?.

Applcation filed December 12, 1914. Serial No. 876,759.

the new nitrogen tungsten lamps. The invention has for its primary objects the provision of a means for securing a proper circulation of air through the shade employed thus preventing excessive t mperatures tending v to injure the lamps; the provision of an improved dust cap construction; and. the provision of improved means for securing the attachment between the glass shade and its metal holder, constructed so as to avoid danger of breakage due to the expansion of the glass against the holding screws and so as to prevent the accidental unscrewing of such screws. Certain embodiments of the invention are illustrated in the accompanying drawings wherein Figure l is a' partial side elevation and partial section taken through the fixture, Fig. 2 is a section taken through the holder and dust cap of a modified'form of construction, Fig. 3 is an enlarged detailed section through the means for securing the holder and shade together at their juncture, and Fig. 4 is a partial plan view of the holding collar or band, and showing the means for securing the two ends of the band together. j

Referring to the general arrangement of parts as shown in Fig. 1; 1 is the source of illumination, in the present case a nitrogen-tungsten lamp supported in the usual socket 2;' 3 is the glass shade provided at its upper edge with the neck portion 4; 5 is the shade holder secured to the upper being screw-threaded into the socket 2 at one end and into the supporting ring 8 at its other end. The dust cap 6 is-held spaced in its proper position by means of the spacing sleeve 9 which is clamped between the holder and the dust cap, the screwing down vof the ring 8 serving to hold these parts securely in position.

The holder 5 is provided with two series of perforations 1O and'll and the dust cap is provided at its upper end with the series ofperforations 12. It will be seen that the perforations 12 are so located that none of the light which escapes through the perforations 10 and 11 will reach these perforations 12. As a result no light spots on the ceiling above the fixture will show. The provision of the perforations 12 serve to permit of a proper circulation of air through the fixture so that injuriously high temperatures are avoided. The provision of the perforations 10 and 11 in conjunction with the perforations 12 and a perforation 13 at'the extreme lower end of ..the shade 3 permits of a vigorous upward circulation of air through the shade, holder and dust cap such as could not be secured if the perforations 12 were not employed and if the air instead of passing out through such perforations had to flow downwardly and pass out through the space 14 intermediate the lower edge of the dust cap and the holder 5. This circulation of air is most important in cases where nitrogen lamps working at high temperatures are employed,-as in such cases and with closed shades hr globes, the temdeterioration of the lamp is caused. Another advantage incident to the free upward circulation lies in the fact that the opening 13 at the lower end of the shade 3 may be made much smaller than if a dust cap without perforations were employed, so that the area of direct light from the lampis reduced in size and the appearance of the fixture improved.

Another feature of invention in my apparatus consists in the use of a band or collar 14 shown in enlarged detail in Figs. 3 and 4. This band is made of sheet metal and is curved at its upper edge with a head 15. As indicated in Fig. 4, the head 15 is cut off at one end of the band, and this portion of the band from which the bead is. removed is provided with a plurality of perforations 16. e

through one of the perforations 16 and bent back upon itself as indicated in Fig. 4. The two ends of the band are thus adjustably selar or band 14 instead of having the screws- One advantage directly engage the glass. lies in the fact that there is less breakage since the spring of the material of the band permits it to give slightly when the glass ex- "pands under the influence of the heat. This yielding or springing of the band is permitted by reason of the fact that it engages the glass at its upper and lower edges only, the portion intermediate these edges being free of the glass. The pressure on the glass is also more evenly. distributed thus tending to resist the breakage. Another advantage lies in the fact that the screws'18 do not accidentally and gradually become unscrewed as in the case where screws are used in direct engagement with the'glass. In this latter construction and incident to the turning of the glass past the screws in washing, the screws gradually become retracted, and the shades sometimes eventually become detached from their holders and fall. I have found that the use of the band 14 prevents this unscrewing action, as the band acts somewhat as aspring nutlock upon the screw and when the globe or shade is turned withrespect to its holder, the glassturns in the collar 14 and there is no movement between the band and the screw tending to retract the screw.

The bead 15 serves to position the screws and prevent their slipping upward upon the band or. collar.

.Fig. 2 illustrates a'modification wherein the holder 5' is similar to that of Fig. 1, but wherein the dust cap 6 is different due to the fact that the tubular supporting member 7 of Fig. 1 is dispensed with. In this construction the supporting ring 8 is screwed directly into the socket 2, and the upper edges of the holder and dust cap are clamped between the parts 2 and- 8. The dust cap such shade, of a spring metal collar in the form of a band with its ends adjacent, lying in said neck so that its upper and lower edges only touch the neck, and screws extending through the holder and engaging the band.

2. The combination with a glass shade having acurved neck and a metal holder for such shade, of a spring metal collar in the form of a band with its ends adj acent,lying in said neck so that its upper and lower edges only touch the neck, a bead on the collar, and screws extending through the holder and engaging the band.

8. The combination .with a glass shade havinga neck and a metal holder for the shade,-of a spring metal collar lying in the neck and engaging the neck at the upper and lower edges of the collar but out of contact with the neck between such edges, and holding screws extending through the holder'and engaging the band intermediate its edges.

4. The combination with a glass shade having a neck and a metal holder for. the shade, of a collar comprising a metal band of sheet metal bent into annular form with a part of the band intermediate the upper and lower edges thereof out of contact with the glass neck, and screws extending through the holder and engaging the part of the band which is out of contact with the glass.

In testimony whereof I have hereunto signed my name in the presence of the two subscribed witnesses.

L. E. GRISWOLD.

Witnesses:

ARCHWORTH MARTIN, M. L. JONES. 

